Abstract: Helmet provided with a signal ensuring the user that the locking of the retention system is totally achieved. In the case represented, the signal is a sound source (9) which is powered by a battery (8). Plate (2) of chin strap (7) is secured to shell (1) and is also part of the power supply circuit for signal (9). The circuit is activated when a force exerted against textile tape (4) by the user's head is sufficient to establish contact between a flexible blade (19) and plate (2). The signal stops emitting when the force disappears, upon removal of the helmet or when the chin strap (7) is sufficiently tensioned towards the inside of the helmet and is therefore properly fastened to separate flexible blade (6) from its contact point on extension (13) of plate (2). The device is particularly adapted to helmets for motorcyclists.

Abstract: A protective motorcycle helmet is provided which has a collar or bead which is substantially concentric with the opening of the shell base of the motorcycle helmet. The perimeter of the collar is a constant and when the helmet is locked in a closed position can open at one point over its circumference in order to remove the helmet from a user and to place it on a user. At least one flexible element extends about the circumference of the helmet shell base. These flexible elements are connected to one end to the helmet shell and at the other end to the collar. This ensures connection between the two elements.